Page 1 of 1

IR Mod

PostPosted: Tue Oct 31, 2006 7:04 pm
by Viz
Has anyone here seen this?
http://lifepixel.com/
Perhaps this is old news...?
I think I know what I will do when I upgrade my body... send it to the next life.

PostPosted: Tue Oct 31, 2006 7:54 pm
by DaveB
Some of us have seen it. ;)

IR is indeed an interesting area of photography!

PostPosted: Tue Oct 31, 2006 9:11 pm
by Viz
Suitably humbled... I'll sit down now.
Now I know where to go.

PostPosted: Tue Oct 31, 2006 10:05 pm
by DaveB
Sorry, I didn't mean to "shut you up".

If you have any questions about it I'll be happy to try answering them. Or someone else around here may have useful comments also...

PostPosted: Wed Nov 01, 2006 12:41 am
by adam
Viz :) Have a look at this website: http://burren.cx/photo/
There are some good articles on that website and he also does camera conversions (in Australia :):))

(I've been wanting to have my G2 converted, but... now I want an IR Pro1 instead :P.)

IR is very interesting! I love it :)

PostPosted: Wed Nov 01, 2006 1:25 am
by Viz
Thank you both, I am not hurt, and it would take serious surgery to shut me up. I was just duly noting an Aussie supplier, and was a bit disappointed that I wasn't a digital Vasco da Gama :) But I have MANY questions and a keen interest. I have had an idea for a while about doing portraits with IR in complete visible darkness, but I haven't known where to start - now I learn about this and I have more ideas - but the prospect is a serious can of worms involving AF bulb changing (and possibly correcting), and speedlight or other high output IR light.... My mind is churning.

First Q. - Is AF possible in visible black, and if I have an IR AF helper light will it focus crisply?

PostPosted: Wed Nov 01, 2006 8:18 am
by Critter
I don't really understand the attraction for IR photogrpahy. Mostly all you see is black grass and white trees, which while interesting once or twice, I find gets boring pretty quickly. Am I missing something, or is IR just a goofy form of B&W?

PostPosted: Wed Nov 01, 2006 8:25 am
by Alpha_7
Critter wrote:I don't really understand the attraction for IR photogrpahy. Mostly all you see is black grass and white trees, which while interesting once or twice, I find gets boring pretty quickly. Am I missing something, or is IR just a goofy form of B&W?


I was going to give you this reference of a brilliant IR shot but the show has been taken down. http://www.dslrusers.net/viewtopic.php?t=18157

It can be more then goofy B&W.

PostPosted: Wed Nov 01, 2006 8:57 am
by DaveB
Viz wrote:I have had an idea for a while about doing portraits with IR in complete visible darkness, but I haven't known where to start - now I learn about this and I have more ideas - but the prospect is a serious can of worms involving AF bulb changing (and possibly correcting), and speedlight or other high output IR light.... My mind is churning.

Certainly you can do IR flash photography: flashes push out IR light as well as visible and you just need to put sheets of IR-pass material (e.g. "Lee 87" polyster film - rated as having a 730nm pass, although I think the 50% transmission is a little higher). Just make sure the film isn't too close to your flash to avoid overheating and burning of the film. The film's available from Vanbar if you're interested, but there are other material options also.
You may find that subjects notice the flash as a deep red pulse, but being red it will have little effect on their vision.

However, in DSLRs any TTL flash metering won't work and you'll need to manually set the flash level. If you're using a compact with TTL flash metering (e.g. PowerShot G1/G2/G3/G5/G6/Pro1 which have an E-TTL hotshoe) the flash metering will work normally (as does Canon's multiple-flash wireless setup).

First Q. - Is AF possible in visible black, and if I have an IR AF helper light will it focus crisply?

AF in the dark may be possible (I haven't tried it) but it would need to be light close to visible (to minimise focussing errors, and to ensure it was seen by the AF sensor).

Critter wrote:Mostly all you see is black grass and white trees, which while interesting once or twice, I find gets boring pretty quickly. Am I missing something, or is IR just a goofy form of B&W?

I wouldn't say that IR is a replacement for visible-light photography (when I'm working I usually have two visible-light cameras and one IR). But it does provide a raft of new options:
  • Another type of B&W (note that some photographers prefer B&W to colour).
    If you know of B&W photographers shooting landscapes with a red filter, this is an extreme form of that.
  • B&W portraits: most skin blemishes disappear.
  • Related to this is wedding photography: many of my customers are wedding photographers.
  • Photography in the dark.
  • Scientific/survey work (e.g. measuring photosynthesising plant cover) in the field (some of my conversions are mounted in kites, some in planes) and in the studio (e.g. analysing paint materials in artworks).
  • With some IR filters you can achieve "false-colour" images. Personally I get more satisfaction out of B&W work, but one of the masters of this is Dave Twede. The cameras I've converted for him actually have no IR filter inside and he takes multiple photos with different external filters so it's a bit of work, but his results are certainly impressive!
I'm sure there are more I've forgotten to mention!


Thanks for pointing that out Craig - I've fixed the link in that post now (my site was reorganised recently).

PostPosted: Wed Nov 01, 2006 9:36 am
by stubbsy
People - At the risk of stating the bleeding obvious (since Dave was too modest to mention it), the Aussie IR site Adam mentions is in fact DaveB's web site so I'm guessing he probably knows a little about the subject :lol:

PostPosted: Wed Nov 01, 2006 10:15 am
by Viz
OK, - I was thinking more of a dedicated IR Flash unit or bulb - or a seriously high output dedicated IR light to bathe the scene, and snap away as desired. My idea of the portraits is getting people off guard, so absolute minimum light is ideal. Could even hook up a pair of video glasses to the camera if it has a live video feed - one of the compacts must. It would be like being a photographer out of Blade Runner or something.

PostPosted: Wed Nov 01, 2006 2:28 pm
by DaveB
The "night vision" illuminators used by some video cameras are made with IR LEDs, although getting decent range out of an LED light source could be tricky. Google for "IR LED" and see what you find.

One thing I found was this PDF list of IR illuminators for the security industry. Note that with the use of IR illumination in security surveillance you might have trouble getting hold of these products without security clearance (although that'd be just those companies' internal systems - there's nothing to stop you making your own similar units, and if you tread carefully you may be able to obtain a unit without security clearance).

PostPosted: Wed Nov 01, 2006 3:18 pm
by Viz
That last one looks good. I think I'll get that one...

I looked at LED manufacturers, but I guess I'd have to start with a functional camera before I start designing a lighting system.

Start up a portraiture business and suddenly a "delivery van" is constantly parked outside my window.

PostPosted: Wed Nov 01, 2006 3:33 pm
by stubbsy
There is some interesting looking info on Colour IR on Bjorn Rorslett's web site HERE

PostPosted: Thu Nov 02, 2006 5:38 pm
by Viz
That was good information

Has anyone here experimented with UV filters on a digital body? I understand that some conversions are made by replacing the hot mirror over the sensor with a neutral substance rather than a specific graded one.. therefore allowing things such as UV experimentation.

I like the difference in PP methods - David here swaps channels, while Bjorn does a grey balance measurement.. I am sure that if I get into it I will experiment with and and sundry. I would love it if someone uploaded any RAW file from any IR camera so we could see a few people's interpretations on colour corrections, I want to have a go in ACR calibration.

PostPosted: Thu Nov 02, 2006 9:22 pm
by NJ
i dont know much at all about shooting IR, but i was wondering how people manage shots such as this one,

http://www.lifepixel.com/digital-infrared/samples3.html

PostPosted: Thu Nov 02, 2006 10:11 pm
by DaveB
Viz wrote:Has anyone here experimented with UV filters on a digital body? I understand that some conversions are made by replacing the hot mirror over the sensor with a neutral substance rather than a specific graded one.. therefore allowing things such as UV experimentation.
If you use generic borosilicate glass it's transparent across a wide spectrum, but for the "CLR" conversion I offer I use Schott WG280 glass (which passes everything from 280nm upwards). 280nm is well into UV and is enough for most people.

Finding the best UV filter for your application can be tricky. Filters such as Hoya's U-330 let in light up to about 400nm (i.e. a band of UV) but then also let IR light in, so you need to combine these filters with IR-blocking filters. If you try to capture both UV and IR at once they'll usually not focus at the same point (think of it as an extreme form of chromatic aberration).
Also many lenses hardly pass any UV light at all... I think it's Bjorn who has info on his site about hand-grinding the UV-retarding coatings off a cheap lens. Specific UV lenses are very expensive. Thus most people end up regarding UV photography as too hard...

I like the difference in PP methods - David here swaps channels, while Bjorn does a grey balance measurement..
Actually I think most people (myself included) start with with a white balance. Swapping channels is a step beyond that.

I would love it if someone uploaded any RAW file from any IR camera so we could see a few people's interpretations on colour corrections
Ok, not much sunshine today, but here's a photo I took with a PowerShot Pro1 (with internal RG715 "R72" filter) at Mungo NP last week.
DNG file (9 MB)
It's not a great photo in any way, but it's a starting point for your play.

ACR's range of colour temperatures doesn't seem to be as wide as some converters: this is the colour achieved by trying to balance off the dirt.
Image

A bit of playing quickly achieved this:
Image

Ok, over to you: what can you do with it?

I want to have a go in ACR calibration.
Normally "ACR calibration" refers to calibrating the colour behaviour using a Gretag-Macbeth ColorChecker target. What are you referring to?

PostPosted: Fri Nov 03, 2006 7:10 am
by Viz
Thank you extremely kindly sir. I can't wait to have a burl at that one Dave. And by ACR I was referring to the last palette Adobe Camera Raw's GUI called "calibration" where you can specify further colour changes before import. I'll post results asap. I'd like to see other's interpretations as well - perhaps an element of psychology and colour theory.

PostPosted: Sat Nov 04, 2006 1:09 am
by Viz
OK, only a crazy or dedicated person works with a camera for 15 hours and then goes home to play in photoshop for another hour with someone else's photo.. I think that I fall under the former category.

It is quite strange, in my view just about everything about the hue and saturation is absolutely wrong, but the luminance is oh-so-right... but how to colour correct?

Image

I did this with 9 adjustment layers in various blending modes - one of which used a gradient mask for the sky - I am sure that my method would be refined... it is a bit over saturated, but I was trying to give it punch and have it make sense like a normal photo.

Thanks again for the DNG - it is actually a cool IR shot - it reminds me of old colour television and film like journey to the centre of the earth or lost in space or something.

EDIT: and now that I compare it to yours mine lacks contrast - I think that this is because I flattened my end result, copied it and pasted it back onto the first history state in colour mode with no curves or levels.